1. Field of the Invention
The present invention relates to a method for preparing halogenated butene and butane. Particularly, it relates to a method for preparing at least one halogenated compound selected from the group consisting of 1,1,1,4,4,4-hexafluoro-2,3-dichlorobutane, 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene, 1,1,1,2,4,4,4-heptafluoro-2-butene and 1,1,1,2,2,4,4,4-octafluorobutane.
2. Related Art
1,1,1,4,4,4-Hexafluoro-2,3-dichlorobutane, 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene and 1,1,1,2,4,4,4-heptafluoro-2-butene are useful as industrial chemicals and as an intermediate for medicines and agricultural chemicals. In addition, these materials can be a raw material to prepare 1,1,1,2,2,4,4,4-octafluorobutane which can be prepared by adding hydrogen fluoride (HF) to these materials, and which substitutes for HCFC and is used as a foaming agent, a detergent and a heating medium. 1,1,1,4,4,4-Hexafluoro-2,3-dichlorobutane, 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene and 1,1,1,2,4,4,4-heptafluoro-2-butene can be reduced to prepare 1,1,1,4,4,4-hexafluoro-butane which is used as the same applications as those of these materials.
It is known that 1,1,1,2,4,4,4-heptafluorobutene can be prepared by fluorinating hexachlorobutadiene with KF. However, this method is commercially unsuitable, since a reaction procedure is complex, a treatment of KC1 produced after the reaction is necessary due to the use of KF, and a cost is high.
It is also known that 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene can be prepared by fluorinating hexachloro-1,3-butadiene with HF in the presence of SbCl.sub.5. However, the antimony catalyst is highly corrosive so that this method is not practically useful due to the absence of a material suitable for a reactor. It is not known to commercially prepare 1,1,1,4,4,4-hexafluoro-2,3-dichlorobutane and 1,1,1,2,2,4,4,4-octafluorobutane.